The BMW M73 B54 is a 5,379 cc, V12 naturally aspirated petrol engine produced between 1996 and 2001. It featured dual overhead camshafts (DOHC), 48-valve configuration, and individual throttle bodies, delivering 240 kW (326 PS) and 490 Nm of torque for flagship luxury applications. This engine used electronic throttle control (Drive-by-Wire) and single VANOS variable valve timing for improved responsiveness.
Fitted exclusively to the E38 7 Series (750i/iL) and E31 8 Series (850Ci), the M73 B54 was engineered for silent, effortless power delivery and ultimate refinement. Emissions compliance was achieved through dual three-way catalytic converters and closed-loop lambda control, meeting Euro 3 standards across its production run.
One documented reliability concern is premature crankshaft position sensor failure, which could result in stalling or no-start conditions. This issue, highlighted in BMW Service Information Bulletin 11 07 97, is attributed to heat exposure and internal component degradation. In 1998, BMW introduced a revised sensor with improved thermal shielding and connector sealing.
Bmw
Production years 1996–2001 meet Euro 3 emissions standards (VCA UK Type Approval #VCA/EMS/8901).
The BMW M73 B54 is a 5,379 cc V12 naturally aspirated petrol engine engineered for flagship luxury platforms (1996–2001). It combines a 48-valve DOHC layout with individual throttle bodies and single VANOS to deliver silent, linear power delivery and high-RPM refinement. Designed to meet Euro 3 standards, it represents the pinnacle of BMW's naturally aspirated V12 engineering.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 5,379 cc | |
| Fuel type | Petrol | |
| Configuration | V12, DOHC, 48-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 84.0 mm × 81.0 mm | |
| Power output | 240 kW (326 PS) @ 5,200 rpm | |
| Torque | 490 Nm @ 3,900 rpm | |
| Fuel system | Sequential multipoint fuel injection (SME) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Double-row roller chain (DOHC) | |
| Oil type | BMW Longlife-98 (SAE 10W-40) | |
| Dry weight | 252 kg |
The M73 B54 provides silent, high-torque performance ideal for flagship grand touring but requires strict adherence to oil and coolant maintenance schedules to prevent sensor and timing system degradation. BMW Longlife-98 (10W-40) oil is critical due to its high-temperature stability and protection for the DOHC valvetrain. Coolant should be replaced every 2 years using G48 specification to maintain flow through the complex V12 cooling passages. The individual throttle bodies demand periodic synchronization via diagnostic tools to preserve throttle response. Post-1998 models with revised crankshaft sensors show significantly improved durability; pre-1998 units should verify sensor condition and consider preventative upgrades per BMW SIB 11 07 97.
Oil Specs: Requires BMW Longlife-98 (10W-40) specification (BMW SIB 11 07 97). Supersedes ACEA A2-97 requirements.
Emissions: Euro 3 certification applies to all M73 B54 models (1996–2001) (VCA Type Approval #VCA/EMS/8901).
Power Ratings: Measured under DIN 70020 standards. Output consistent across EU fuel grades (RON 95).
BMW Technical Information System (TIS): Docs A28010, A28011, A28012, SIB 11 07 97
VCA Type Approval Database (VCA/EMS/8901)
DIN Deutsches Institut für Normung: DIN 70020 Engine Power Measurement
The BMW M73 B54 was used across BMW's E38/E31 platforms with longitudinal mounting and no licensed external applications. This engine received platform-specific adaptations-increased cooling capacity in the E38 and revised intake manifolds in the E31-and from 1998 the updated crankshaft position sensor with improved thermal shielding, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-left side of the engine block near the exhaust manifold (BMW TIS A28010). The 7th VIN digit indicates engine family ('M' for M73 series). Pre-1998 models have silver valve covers with "M73" branding; post-1998 units use black valve covers with "M73B54" designation. Critical differentiation from M73TÜ: Original M73 B54 lacks secondary air injection system; M73TÜ includes air pump for emissions. Service parts require casting verification - crankshaft position sensors before 09/1998 are incompatible with later revisions due to connector and shielding redesign (BMW SIB 11 07 97).
The M73 B54's primary reliability risk is crankshaft position sensor failure on early builds, with elevated incidence in vehicles with extended service intervals. Internal BMW field reports from 1998 indicated a significant number of pre-1998 units required sensor replacement before 150,000 km, while UK DVSA records show electrical faults as a top cause of immobilization in E38/E31 petrol models. Extended service intervals and heat exposure increase sensor stress, making inspection and schedule adherence critical.
Analysis derived from BMW technical bulletins (1996-2001) and UK DVSA failure statistics (1998-2008). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW M73B54-54122.
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